1. Field of the Invention
The invention relates to a method of optimizing a write current for at least one rotatable magnetic head by means of which a magnetic tape can be scanned along tracks which are inclined relative to the longitudinal direction of the magnetic tape in consecutive scanning periods, a write current being applied to the magnetic head as a test signal with a given number of graded amplitude values within a given time interval and this test signal being recorded on the magnetic tape by the magnetic head, and the recorded test signal being scanned from the magnetic tape and the level values of the scanned and reproduced test signal, which correspond to the graded amplitude values of the write current recorded as the test signal, being determined, and an optimum amplitude value of the write current being determined from the level values thus determined.
The invention also relates to an arrangement for carrying out a method of the type defined in the opening paragraph, for optimizing a write current for at least one rotatable magnetic head of the arrangement, by means of which a magnetic tape, which can be driven in the arrangement in the longitudinal direction of the tape, can be scanned in consecutive scanning periods along tracks which are inclined relative to the longitudinal direction of the tape, which arrangement comprises a control device and a write current generator adapted to generate a write current as a test signal with a given number of graded amplitude values, which write current generator is controllable by the control device to generate the different amplitude values of the write current and is connected to the magnetic head to supply the generated write current to this magnetic head, and a processing device by means of which the level values of the scanned and reproduced test signal, which correspond to the graded amplitude values of the write current recorded as a test signal, can be determined, and a logic device by means of which an optimum amplitude value of the write current can be determined from the level values thus determined.
2. Description of the Related Art
A method of the type defined in the first paragraph and an arrangement of the type defined in the second paragraph are known from DE-A1 41 18 533. In this known method and in the known arrangement, the generation and application of the given number of graded amplitude values of a write current applied to a magnetic head as a test signal in total cover a plurality of scanning periods of the magnetic head, so that the test signal is recorded in a plurality of oblique tracks. It is therefore obvious that the reproduction and processing of the scanned and reproduced test signal also cover a plurality of scanning periods. As a result of this, the known method of optimising a write current for at least one rotatable magnetic head takes a comparatively long time of a few seconds, which is annoying to the user of, for example, a video recorder using the known method. Moreover, since the reproduction and processing of the recorded test signal cover a plurality of scanning periods and hence a plurality of oblique tracks, the known method and the known arrangement also have the disadvantage that a poor tracking and changes in the tracking of a magnetic head which scans and reproduces the recorded test signal have an adverse effect on the measurement accuracy for the different values of the level of the scanned and reproduced test signal.